1. Field of the Invention
The present invention relates to a turbojet-engine thrust reverser having downstream baffles designed to be mounted on turbojet-type aircraft engines with bypass or single flow.
2. Description of the Related Art
French patent document 2,622,928 A illustrates one design of a thrust reverser having downstream baffles and implementing thrust reversal of the bypass, or cold, flow of a bypass turbojet-engine. This kind of thrust reverser comprises downstream or clamshell baffles which, besides implementing the reversal of either the bypass flow or the whole flow, also constitute the exhaust nozzle in the forward-thrust mode. The downstream edge of said baffles therefore constitutes the downstream end of the of the outer duct wall, in the latter case of the annular circulation duct of the bypass flow where a bypass turbojet-engine is concerned. The baffles are pivotably mounted on the stationary thrust-reverser structure.
FIGS. 1 and 2 of the attached drawings show an embodiment of this kind of a known thrust reverser in the forward-thrust mode and in the thrust reversal mode, respectively. In this instance, the thrust reverser consists of a stationary upstream structure 1 affixed to the turbojet engine or its cowling and comprises an inner wall externally bounding the annular duct for circulation the flow, an external stationary fairing affixed to the inner wall, and two side structures 5. Two downstream baffles 2 are pivotably mounted on the stationary structure, in particular by pivots 10 resting on the side structures 5 which also support a control system 6 for the displacements and the locking of the baffles 2. In this embodiment, a linkrod 7 connects, by its end 8, the movable part of the actuator 6 to the baffle 2 at a point 9. The downstream edge 4 of the baffles 2 constitutes the trailing edge of the outer wall by extending the fairing in the downstream direction and is not coplanar. At its upstream end, the baffle 2 comprises a spoiler 12 for guiding the reversed flow.
In the known solutions according to French patent 2,348,3712 A, U.S. Pat. NO. 5,176,340 or British patent 2,252,279 A, wherein the pivots of the downstream baffles are stationary, these baffles incur the drawback that their inner contour is unchanging relative to their outer contour. As a result, when in the extended position, the orientation of the inner contour depends on the global displacement of the baffle, this displacement being restricted to making contact with the downstream edge of said baffles in order to increase thrust-reverser efficiency. This design entails an oblique, downstream cutout in the nozzle exhaust, and consequently incurs aerodynamic losses in the forward thrust mode. Such losses are eliminated according to the U.S. Pat. No. 5,176,340 and British patent 2,252,279 A by a dedicated mechanical system associated to the baffles.
According to British patent 2,168,298 A, the baffle comprises of an outer and an inner panel. However, this baffle incurs the major drawback of the panels fitted with independent control systems, resulting in an increase in weight and in problems synchronizing movement of the two panels. Moreover, the technology is restrained to central pivoting, thus being required to have a downstream deviation of the internal panel entailing a large central gap and a downstream deviation of the external panel obliquely covering, over the internal panel with discontinuity of the streamlines. These associated components cause large aerodynamic perturbations in the forward-thrust mode.